Heretofore, this type of thermal print head is composed by attaching a ceramic heating board onto the upper surface of a metallic radiating plate. A heating resistor for printing, a common electrode pattern and an individual electrode pattern are formed on the surface of the heating board and plural IC chips for driving are mounted. In case the heating board having the configuration described above is attached to the radiating plate, an adhesive and a pressure sensitive adhesive tape are generally used, however, in any case, precise positioning is required and particularly, to position precisely in the longitudinal direction of the heating board, that is, in the direction of the x-axis which is a direction in which the heating resistor is arranged, heretofore, a first dot part (the leading end) and a last dot part (the trailing end) of the heating resistor linearly formed on the heating board are based.
That is, the first dot part and the last dot part of the heating resistor are directly recognized as a binary number by a camera and others, the heating board is precisely set on the radiating plate and is bonded based upon it.
However, recently, the demand of a thermal print head wherein a heating resistor is covered with a conductive protective coat is increased and a problem that precision in bonding between a heating board and a radiating plate decreases because such a conductive protective coat is formed occurs.
That is, as a heating resistor is generally black, while a conductive protective coat is also approximately black, it is difficult to recognize the first dot part and the last dot part of the heating resistor by a camera and as a result, misregistration by wrong recognition occurs.
Therefore, it is considered that an identification mark different from a heating resistor is required and is based, however, wrong recognition is caused depending upon the shape of a mark and satisfactory bonding precision is not achieved. The object of the invention is to provide a thermal print head wherein an identification mark for positioning enabling solving such problems is provided.